As a molecular modeler, it’s common to examine distances, angles, or torsions between atoms—but it’s equally common to lose track of those measurements when switching views or making a new selection. If you’ve ever thought, “Where did my previous distance go?” you’re not alone.
By default, SAMSON creates temporary measurements when using the Measure editor. These appear immediately and remain visible regardless of zoom level—but they’re transient. As soon as you perform another measurement, the previous one disappears. This is by design, but it can be inconvenient if you’re comparing multiple conformations, preparing a figure, or simply trying to keep track of complex spatial relationships.
Preserving Measurements with Labels
The good news is that converting a temporary measurement into a permanent one takes a single keystroke. Once you’ve clicked on atoms or bonds to create a measurement:
- Press Enter.
This simple action turns your live measurement into a label, which is saved in the document. Labels persist throughout the session and after saving, even across restarts if you save your document as a .sam or .samx file.
Why Labeling Matters
Labeling a measurement not only preserves it, but also unlocks more capabilities:
- Permanent visibility: Labels appear at appropriate zoom levels and remain in the document until deleted.
- Customization: You can change font, color, and positioning via the Inspector.
- Detailed information: For atom-atom distances, projections on molecular planes are also available.
When you select a label in the interface, the related atoms are highlighted, and you can explore further details in the Inspector, such as measurement values per axis or visualization plane.
Combining Insight with Visual Clarity
By labeling measurements instead of relying on temporary ones, you’re able to:
- Prepare figures for publication with consistent annotations
- Communicate spatial relationships in collaborative projects
- Keep track of changes across minimizations or molecular dynamics simulations
And here’s an extra advantage: measurement labels update automatically if atomic positions or charges change. This makes them perfect companions for use while applying move editors or force field minimizations. Whether you’re adjusting a geometry by hand or within a workflow, your saved distances and angles remain current and meaningful.
Saving Time and Frustration
Small features can make big differences in daily work. If you’ve been re-measuring distances over and over, or manually writing notes to remember them, switching to persistent measurement labels in SAMSON could save time and reduce errors. Plus, your work is more reproducible and easier to share.
To learn more, visit the full SAMSON measurement documentation.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.